CHAPTER XI. 



1. A regular muscle-prism ; 2. Currents and tensions in a musele- 

 prism ; 3. Musole-rhombus ; 4. Irregular muscle- rhombi ; 5. Cur- 

 rent of VI. gastrocncviiKS. 



1. Beginning the study of the electric phenomena 

 exhibited in animal tissues with muscles, we will at first 

 experiment only with single, extracted muscles; Even 

 these, however, exhibit phenomena so complex in some 

 respects, that it will be better to take first a compara- 

 tively simple case. In taking one not exactly under 

 natural conditions— if, that is, we use a muscle artifi- 

 cially prepared for the purpose of experiment — this pro- 

 ceeding will find ample justification in the greater ease 

 with which we shall thus be enabled to understand the 

 more complex examples which we must afterwards 

 examine. 



Taking a regularly shaped muscle, in which the 

 fibres are parallel, we will cut out a part of this by 

 making two even cuts at right angles to the direction 

 of the fibres. A piece of this sort may be called a 

 regular T^iuscle-jprisin. It is, according to the shape of 

 the muscle used, either circular or more oval, or flat 

 and band-like ; its shape makes no difference, and the 

 length and diameter are of equally little account. The 

 only essential point is that all the muscle-fibres are 



